
Solid State Logic (SSL)
Harrison Audio MR3eq 500 module
Configurer
Harrison Audio MR3eq is a fully analog 500-series equalizer that directly inherits the circuitry of the legendary Music Recording 3 (MR3) console from 1981. This module brings the punchy, smooth, and highly musical Harrison sound to modern hybrid outboard setups, preserving a sonic signature that has shaped countless classic albums over the past four decades.
Musical Sculpting via Proportional Q
Standard equalizers often force engineers to choose between surgical precision and broad, musical tone shaping. The MR3eq solves this bottleneck through its mid-band (400 Hz – 8 kHz), which utilizes a continuously variable Proportional Q design. As the boost or cut deepens, the filter bandwidth narrows automatically. This allows for pinpoint removal of harsh resonances at extreme gain settings, while subtle adjustments yield wide, gentle curves perfect for seating vocals or acoustic instruments seamlessly into a mix. The high and low bands default to musical 6 dB/octave shelves, but can instantly be switched to 2nd-order bell curves, vastly expanding the unit's versatility for tracking drums or bass.
Resonant HPF for Focused Low-End
Heavy-handed low-frequency filtering can easily neuter the foundation of a mix, leaving tracks sounding thin and lifeless. Harrison addressed this by giving the MR3eq a completely independent High-Pass Filter (HPF) circuit featuring a distinct resonant peak at the corner frequency. As you roll off sub-harmonic rumble and stage bleed, the filter simultaneously adds a slight bump right above the cutoff point. This psychoacoustic trick cleans up the low-end mud while preserving the perceived physical weight and punch of the source material.
KEY FEATURES
- Authentic 3-band equalizer circuitry derived from the 1981 Harrison MR3 recording console.
- Independent High-Pass Filter circuit with a characterful resonant peak to retain low-end punch.
- Continuously variable Proportional Q design on the mid-frequency band for dynamic bandwidth control.
- Switchable High and Low bands, allowing seamless toggling between a 6 dB/octave shelf and a 2nd-order bell response.
TECHNICAL SPECIFICATIONS
- Format: Single-slot 500 Series module.
- Gain Range: +/- 10 dB of boost/cut across all three bands.
- LF Band (Low): 40 Hz - 800 Hz.
- MF Band (Mid): 400 Hz - 8 kHz.
- HF Band (High): 800 Hz - 15 kHz.
- Hardware Extras: Dedicated "In" bypass switches for both the EQ and HPF sections, and an integrated input overload LED indicator.

